An IAM access key is a long-term AWS credential used to sign and authenticate API requests. It typically comes as an access key ID and a secret access key, and it identifies an AWS principal such as a user or automation account. Because it is not tied to an interactive login session, it can be embedded in scripts, applications, and deployment tools.
In cyber security, IAM access keys matter because a leaked key can give an attacker direct access to cloud resources. If permissions are too broad, the key may be used to list data, create new resources, or generate additional credentials for persistence. Defenders look for exposed keys in source control, rotate them quickly, and prefer temporary credentials and IAM roles. AWS can also quarantine exposed keys by attaching restrictive policies that block dangerous actions, limiting the damage window after a leak.